Reefer madness: Refrigerated supermarket trucks are but one link in our gas-guzzling food chain.Photo courtesy Paul Sullivan via FlickrIn his recent The New York Times op-ed, “Math Lessons for Locavores” — debated at length in our “Food Fight” feature — Stephen Budiansky shows that transportation and “modern” (i.e., highly mechanized and chemical-intesnsive) farming make up relatively small parts of industrial food’s energy footprint. Consumers in their kitchens, in Budiansky’s view, are the real energy guzzlers — so locavores should stop worrying and learn to love industrial food.

Those points are addressed broadly by a recent article in Amber Waves, the publication of the USDA’s Economic Research service. On page 13 of this lucidly written report, we find that in 2002, U.S. households used nearly 4 quadrillion BTUs of energy in the kitchen, more than any other sector of the food system. By contrast, transportation — think of the vast fleet of trucks that ferries the food we eat cross-country, to supermarket chains and eateries — consumed about 0.6 quadrillion BTUs. And agriculture, with its gas-dependent combines and other machines and fossil fuel-sucking fertilizers and pesticides, used just 2.1 quadrillion BTUs.

For Budiansky, these facts exonerate the industrial food system in energy-use terms. He concludes:

The relative pittance of our energy budget that we spend on modern farming is one of the wisest energy investments we can make, when we honestly look at what it returns to our land, our economy, our environment and our well-being.

But a closer look at the Amber Waves report paints a much more complex picture. What you find is that the accelerating flight to convenience in the U.S. diet — the Trader Joe’s “prepared meals,” the supermarket roast chickens, the endless dinners and lunches out — is turning the food system into an ever-more prolific user of energy. So is the meat industry’s relentless drive to scale up and substitute technology for human labor. And even the hoary concept of “food miles,” or the distance food travels from farm to fork — much disdained by the likes of Budiansky — plays a role in creating a BTU-gulping food system.

Here are a few key points from the report:

Even as overall U.S. energy use levels off, the food system’s energy appetite is growing steadily. Between 2002 and 2007, total per-capita energy production fell 1 percent; but over the same period, food-related per-capita energy use grew nearly 8 percent “as the food industry relied on more energy-intensive technologies to produce more food per capita for more people,” the report states. That trend has been building for at least a decade — in the 1997-2002 period, “over 80 percent of the increase in annual U.S. energy consumption was food related.” By 2007, food-related activities were claiming a hefty 16 percent of the U.S. energy budget.

Greater use of “energy-intensive technologies” explains the bulk of growth in the food system’s energy demand. About a quarter of the growth in food-system energy use between 1997 and 2002 can be explained by population growth; and another quarter came from people simply buying more food, representing a triumph of food industry marketing. But fully half of the increase stemmed from the industry and households shifting to more energy-intensive methods for processing, storing, and cooking food. The report detects that a “shift from human labor to energy-using equipment occurred for all food and food-related commodity groups, except pork.” (The author doesn’t state it, but I will: by 1997, pork production had already become highly mechanized and energy-intensive.)

The egg industry, currently in the headlines for its ignominious hygiene practices, made a dramatic leap in energy use recently. The report claims per-egg energy consumption surged 40 percent between 1997 and 2002, due to “high-technology, energy-intensive hen houses, and more use of liquid, frozen, and dried egg products (instead of whole eggs).” Salmonella-tainted eggs — now with even more embedded energy!

People are increasingly using lots of electric gadgets in place of good old knives, cutting boards, and sponges — and hauling so much food home from the supermarket that they’re buying extra fridges to fill up. Between 1993 and 2005, the percentage of households owning dishwashers jumped from 45 percent to 58 percent. Over the same period, the second-fridge ownership rate went from 15 percent to 22 percent. All of that coal burning to run second fridges is particularly stunning, given that half of food produced in the United States ends up tossed, according to Tristam Stuart’s 2009 book Waste.

While households are indeed massive users of energy in the food chain, energy consumption by the food-processing industry is growing even faster. Between 1997 and 2002, “food processors’ energy use (direct and embodied) grew 49 percent, a larger increase than any other segment of the food system,” the report states. Part of the reason for the jump is increasing consumer demand for prepared food — stuff like “single serving” packaged meals you bring home and pop in the microwave. Get this:

In 1985, 18- to 64-year-olds spent an estimated average of 49 minutes on cooking and cleanup per day. Bureau of Labor Statistics’ data indicate average cooking and cleanup times per household fell to 31 minutes per day in 2008.

The other major factor is that the food-service industry — everything from restaurants to institutional kitchens such as those in hospitals and schools — is also increasingly outsourcing its cooking to the processing industry. In other words, they’re reheating processed junk and serving it up to the public. The basic trend is toward substituting fossil energy for human labor, the report shows.

People are increasingly flocking to “food service establishments” in lieu of cooking and eating at home — and burning more and more energy in the process. “In 2002, 479,000 food and beverage service establishments operated in the United States, up 7 percent from 1997,” the report states. “By 2008, this number increased to 546,000.” As a result, “between 1997 and 2002, industry energy use increased 47 percent.”

It’s true that transportation claims a relatively small share of the food system’s energy use, but we’re still burning increasing amounts of fossil fuel to haul food around — and industry consolidation is the main reason. Energy consumption by the food-transport sector jumped 24 percent between 1997 and 2002. Why? The report states it bluntly:

The trend toward fewer and larger farms and processing plants led to greater use of freight services and substantial increases in the average distance per domestic shipment of all foods between 1997 and 2002.

Agriculture’s share of food’s energy budget is also relatively small — but it, too increased significantly. The report offers scant comment on agriculture’s energy use, but it includes a chart showing that it jumped from about 1.6 quadrillion BTUs in 1997 to 2.1 quadrillion BTUs in 2003. That’s about a 30 percent hike. And starting in 2007, when government corn-ethanol mandates kicked in, use of fertilizers synthesized from natural gas and other agrichemicals rose accordingly. So I would be highly surprised if the rise in on-farm energy use didn’t continue.

When observers like Budiansky dig deep into energy use and the food system, they marvel at the efficiency of the industrial food system and scold people for seeking alternatives. But when I look, I see an energy-ravenous beast skulking unaware into an energy-uncertain future. Eating seasonably and reasonably close to home; supporting diverse, low-input, human-scale farms; cutting down on waste; learning to cook at home from scratch — after reading the USDA’s report, all that seems even more like solid advice.